But the 21-year-old says the switch was down to football reasons, not that he is from the Catholic community.
"They obviously go straight to religion but I can't stress enough that that's got nothing to do with it," he said.
Began career as a youth player at Everton
Joins Coleraine in September 2009
Brought to Torquay United by Paul Buckle in January 2010
Decides to play for Republic of Ireland in September 2011
"I just felt my opportunity wasn't going to come playing for Northern Ireland and the Republic have come and asked me to come and join them, so it's kind of a no-brainer to take the decision to the country that want you," O'Kane told
BBC Radio Devon.
"I just want to play football and if the Republic are going to give me that chance then I'm prepared to take it."
O'Kane, who has won four caps for Northern Ireland Under-21s, would not disclose exactly what discussions he had had with the Irish FA about his decision.
"There's a lot of things that go on that not a lot of people know about," he added.
"I'm not going to come out and say what's really happened behind closed doors because that's nothing to do with anyone else."
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